title: Effect of calcium chloride solution immersion on surface hardness of restorative glass ionomer cements.
abstract: The objective of this study was to evaluate the effect of the concentration of calcium chloride (CaCl2) solution on the surface hardness of restorative glass ionomer cements (GICs). Two high-viscosity GICs, Fuji IX GP and GlasIonomer FX-II, were immersed in several concentrations of CaCl2 solution for 1 day and 1 week. The immersed specimen surfaces were evaluated using microhardness testing, grazing incidence X-ray diffraction, and energy-dispersive X-ray spectroscopy. Immersion in a higher concentration of CaCl2 solution produced a greater increase in the surface hardness. No crystalline substance was observed on the immersed surface. Calcium ions were selectively absorbed in the matrix of the GIC surface after immersion. They reacted with the non-reacted carboxylic acid groups remaining in the cement matrix. These reactions were considered to cause an increase in the surface hardness of the GICs.
authors.affiliation: Advanced Biomaterials, Department of Restorative Sciences, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University.
authors.forename: Maho
authors.initials: M
authors.lastname: Shiozawa
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Naohiko
authors.initials: N
authors.lastname: Iwasaki
authors.forename: Motohiro
authors.initials: M
authors.lastname: Uo
mesh_terms: D002122:Calcium Chloride / Q000737:chemistry*; D005899:Glass Ionomer Cements; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012996:Solutions; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D005899:Glass Ionomer Cements; D012996:Solutions; D002122:Calcium Chloride